The choice of timing for diuresis renography: the F+0 method

Objective To investigate a method of diuresis renography where the radiopha rmaceutical and frusemide (diuretic) are given simultaneously, in contrast to conventional renography which involves an intravenous injection with fru semide 20 min after administering the radiopharmaceutical (F+20) or 15 min before (F-15), with particular interest in the effect of this change on ass essing split renal function and interpreting upper tract drainage dynamics. Patients and methods In a prospective study, 29 patients (18 women and 11 m en, mean age 47 years, range 21-86) were assessed, Each patient had two ren ograms taken over a 48-h period, either by the F+20 or F-15, and the F+O me thod, Data for split renal function and drainage curves were obtained in th e usual way, Two independent assessments of the drainage curves were obtain ed and the results compared. Results The split function assessments were identical (<5% variation) in al l but two patients; 26 of 29 (90%) gave identical conclusions about the dra inage curves. The three patients with discrepancies between the studies had either hugely dilated upper tracts or otherwise had multiple complicating factors, e.g. impaired renal function, neuropathic bladder. Conclusions F+O renography has been used in paediatric urological practice before, but there are no comparative studies and no data on its use in adul ts, This prospective study confirmed that in investigating dilated upper tr acts, the F+O technique gives similar results to the conventional technique s. The F+O method has the potential to reduce the time required to undertak e standard F+20 renography but it may not be useful in evaluating the gross ly dilated upper tract, where the F-15 technique has the best record in ter ms of reducing equivocal results.